Sifat Mekanik Komposit Sandwich CFRP/ABS/CFRP yang Difabrikasi Menggunakan Metode Bladder Compression Molding (BCM)

MUHAMMAD UMAR A A, Dr. Gesang Nugroho, S.T., M.T.

2023 | Skripsi | S1 TEKNIK MESIN

Perkembangan material yang diproduksi dengan Additive Manufacturing (AM) telah berkembang pesat. Salah satu penemuan terbaru adalah komposit sandwich dengan core berupa Acrylonitrile Butadiene Styrene (ABS) hasil Fused Deposition Modeling (FDM) serta kulit berupa Carbon Fiber-reinforced Polymer (CFRP). Tujuan penggabungan ini adalah untuk meningkatkan kekuatan mekanik ABS yang tergolong rendah. Akan tetapi, apabila metode fabrikasi masih menggunakan hand lay-up, maka kekuatan komposit sandwich tersebut masih belum maksimal. Metode Bladder Compression Molding (BCM) diperkenalkan sebagai metode alternatif karena mampu menekan laminasi secara optimal selama curing. Tujuan penelitian ini adalah untuk membandingkan sifat mekanik komposit sandwich CFRP/ABS/CFRP yang difabrikasi menggunakan metode BCM dan hand lay-up. Spesimen pengujian tersusun dari inti (core) berupa ABS hasil 3D printing tipe FDM serta kulit (skin) dari carbon fiber twill weave 3K 220 gr/m2. Matrik yang digunakan adalah resin epoksi jenis Bisphenol A-Epichlorohydrin (Epoksi A) dengan katalis Cycloaliphatic Amine (EPH 555). Tekanan operasi yang digunakan pada metode BCM adalah 3 bar. Sifat mekanik spesimen diperoleh melalui pengujian tarik ASTM D638-14 dan pengujian bending ASTM C393-00. Spesimen metode BCM menghasilkan kekuatan tarik, modulus elastisitas, specific strength, facing bending stress, dan core shear stress masing-masing sebesar 70,976 MPa, 2,991 GPa, 55,74 kNm/kg, 444,013 MPa, dan 3,259 MPa sedangkan metode hand lay-up sebesar 51,189 MPa, 2,617 GPa, 40,836 kNm/kg, 105,134 MPa, dan 2,462 MPa. Selain itu, peningkatan kekuatan tarik, modulus elastisitas, dan specific strength terhadap spesimen ABS monolitik dari metode BCM masing-masing sebesar 401,56%, 201,2%, dan 406,36% sedangkan metode hand lay-up sebesar 261,73%, 167,31%, 270,97%. Dari hasil pengujian dapat disimpulkan bahwa metode BCM mampu menghasilkan sifat mekanik komposit sandwich CFRP/ABS/CFRP yang lebih baik dibandingkan metode hand lay-up.

The development of materials made by Additive Manufacturing (AM) techniques has grown rapidly. One of the latest inventions is a sandwich composite with Acrylonitrile Butadiene Styrene (ABS) from Fused Deposition Modeling (FDM) as a core and Carbon Fiber-reinforced Polymer (CFRP) as a skin. The purpose of this combination is to increase the mechanical strength of ABS which is relatively low. However, if the fabrication method still uses hand lay-up, then the strength of the sandwich composite is still not maximized. The Bladder Compression Molding (BCM) method was introduced as an alternative method because it can provide optimal pressure on the laminate during the curing process. The purpose of this study is to compare the mechanical properties of CFRP/ABS/CFRP sandwich composites fabricated using BCM and hand lay-up methods. The test specimens consisted of ABS from 3D printing FDM as a core and carbon fiber twill weave 3K 220 gr/m2 as a skin. The matrix used is an epoxy resin of Bisphenol A-Epichlorohydrin (Epoxy A) with a Cycloaliphatic Amine (EPH 555) as a catalyst. The operating pressure used in the BCM method is 3 bar. Mechanical properties of the specimen were obtained through ASTM D638-14 tensile test and ASTM C393-00 bending test. The BCM method specimens produced tensile strength, modulus of elasticity, specific strength, facing bending stress, and core shear stress of 70.976 MPa, 2.991 GPa, 55.74 kNm/kg, 444.013 MPa, and 3.259 MPa, respectively, while the hand lay-up method was 51.189 MPa, 2.617 GPa, 40.836 kNm/kg, 105.134 MPa, and 2.462 MPa, respectively. In addition, the increase in tensile strength, elastic modulus, and specific strength of the monolithic ABS specimens from the BCM method was 401.56%, 201.2%, and 406.36%, respectively, while the hand lay-up method was 261.73%, 167.31%, 270.97%. From the test results, it can be concluded that the BCM method can produce better mechanical properties of the CFRP/ABS/CFRP sandwich composite than the hand lay-up method.

Kata Kunci : 3D printing, komposit sandwich, bladder, sifat mekanik